package com.zhouys.response;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

public class FileServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //1、获取下载文件的路径
        //使用相对路径的时候文件地址会出错
        //String realPath = this.getServletContext().getRealPath("/1.jpg");
        String realPath = "H:\\java\\servlet\\response\\src\\main\\resources\\1.jpg";
        System.out.println("下载文件的路径"+realPath);
        //2、下载的文件名是啥
        String filename = realPath.substring(realPath.lastIndexOf("\\") + 1);
        //3、设置想让浏览器能够支持下载我们需要的东西
//        resp.setHeader("Content-Disposition","attachment;filename="+filename);
        //URLEncoder.encode(filename,"UTF-8")中文编码
        resp.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(filename,"UTF-8"));
        //4、获取下载文件的输入流
        FileInputStream fileInputStream = new FileInputStream(realPath);
        //5、创建缓冲区
        int len = 0;
        byte[] buffer = new byte[1024];
        //6、获取OutputStream对象
        ServletOutputStream outputStream = resp.getOutputStream();
        //7、将FileOutStream流写入到buffer缓冲区
        while ((len=fileInputStream.read(buffer)) >0 ){
            outputStream.write(buffer,0,len);
        }
        //8、使用OutputStream将缓冲区中的数据输出到客户端
        //关闭连接
        fileInputStream.close();
        outputStream.close();





    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }
}
